The Common Purple Lilac is well-known and loved by gardeners all over the world for its beauty and fragrance; one of the most powerful fragrances emitted by a plant. It has light purple flowers occurring in clusters amid the dark-green heart-shaped leaves. This hardy, deciduous shrub can withstand severely cold winters, and in fact the species does not grow well in areas without significant frost in wintertime. Lilac produces suckers - new shoots that sprout from the base of the shrub, or from the roots. It is preferable to prune the shrub to emphasize medium-aged wood, which will produce good blooms and still lend good size to the plant. Old flowers should be removed as soon as they fade. The best time to prune is just after flowering. Remove one-third of the oldest stems at ground level every year. Older lilacs can be pruned as small multiple-branched trees, removing sucker growth and emphasizing a few large, old trunks. The shrub also can be trimmed into a single stemmed tree. Overgrown lilacs can be cut to within a few inches of the ground. Within 3-4 years they will flower again. For a hedge, plant about 3-4 feet apart.